When travelling, we recommend packing in preparation to handle common weather conditions. The rainfall in Newquay is typically greater than that of Kansai. We can gather that this will continue over the next 25 days.
You can imagine temperatures to be in the 33 °C range in August. The weather in Kansai is generally hotter than Newquay's. As flight availability is subject to become more limited as peak season approaches it is ideal to book in a timely manner.